Heretofore, various apparatus for removing relatively large machined chips have been proposed and utilized for treating these chips as produced by machine tools. However, these apparatus cannot remove fine chips, which in turn are collected together with a machining fluid in a coolant tank and precipitated therein. Thus, if a large amount of the fine chips precipitates in the coolant tank, a capacity of the tank is insufficient for the machining fluid, which overflows from the tank. As a result, a fire accident may occur due to oil property of the fluid. Further, circulation of the unremoved chips together with the fluid may block an ejecting nozzle for the fluid thereby to cause damage of the tools and worse quality of machined works. Furthermore, a setting disorder may arise in a machining center upon replacement of automatic tools, thereby to adversely affect a machining accuracy.
In view of the foregoing, an apparatus of such a type has been proposed that a conventional coolant tank is provided at its inner bottom with a screw conveyor for removing the precipitated chips therefrom. In such type of apparatus, however, the conveyor was generally arranged horizontally in consideration of its conveying capacity and was impossible to be arranged obliquely for the purpose of reducing a setting area.
Since most of the machined chips are generally magnetic in nature, an apparatus provided at its bottom with a magnetic plate has also been proposed to aggregate the magnetic chips at the bottom within the tank, from which they are scraped and removed by a scraper. Such apparatus, however, necessitates also enlargement of a setting area for the magnetic plate in order to increase the aggregation, thereby to require a large size of the scraper. Thus, the apparatus becomes necessarily large, thereby to raise an equipment cost.
Accordingly, it has long been needed to provide an apparatus for treating chips, which is compact and achieves efficient recovery and removal of the chips, as well as reduction of the equipment cost.
It has now been found out that an apparatus comprising a separating cylinder of a non-magnetic material, such as stainless steel, which is provided at its outer periphery with a plurality of magnetic plates spaced apart each other and contains therein a screw conveyor constructed of a non-magnetic material, allows the chips suspended in a machining fluid to be magnetised by a magnetic-inducing effect generated within the cylinder thereby to be attracted and deposited onto an inner surface of the cylinder and then to be scraped efficiently by the screw conveyor which transports the scraped chips to the outside.
Thus constructed apparatus or the magnetic separator is possible to attract any magnetic materials in the suspension onto the whole inner wall of the cylinder and to surely scrape and transport the attracted chips to the outside. As a result, the cylinder or the separator may be inclined at an angle up to 90.degree. relative to the horizontal plane, thereby to achieve considerable reduction of the volume and the setting area of the separator.
Accordingly, a general object of the invention is to provide a magnetic separator which is compact but achieves an efficient removal of chips from a suspention, reduction of a setting area and hence an equipment cost, as well as convenient control and maintenance.